The official stated position of the USA is to never negotiate with Terrorists or kidnappers, etc. That is the only rational policy to follow. To underscore that there is Nigeria.
Seems their country saw a rash of kidnappings during their current civil war – they made a deal with the devils, and they granted unconditional pardons and cash payments to the evil doers. But that “brought about a short period of reprieve, but has not been successful in quelling the targeted violence in mostly impoverished the region.”
As for the USA policy- not long ago they paid a “ransom”or so called “blood Money” for the release of a CIA contractor in Pakistan. I am sure that there are numerous instances of the US government paying off to effect the release of US citizens – for instance where did the money come from recently to pay the “bail” for the two American hikers kidnapped by Iran. It certainly was not “bail” since it will not be returned because the hikers will not be going back to stand trial. It was a payoff to a thug government.